Flame detectors are in use in many environments, typically hazardous locations such as refineries, chemical plants, compressor stations, and fuel loading facilities. Flame detectors typically have an optical field of view, within which the detector has sensitivity to detect flames within range of the detector. The individual flame detectors are typically connected together to form a network of flame detectors configured to cover a larger area, as part of a detection system which in turn may be part of a fire suppression and/or alarm system. Flame detector coverage is critical because it determines the effectiveness of the system to fight a fire and to warn of the danger.
When a flame detector is unable to see an incipient fire, either because its optical field of view is blocked by an obstruction bigger than the fire, or because the incipient fire is at the periphery of the detector's optical field of view (where the detector's sensitivity is typically at its lowest), the flame detection system will not react with the planned fire mitigation action. In this case, the flame detection system is deemed less effective due to poor detection coverage.
The flame detection system may eventually react at a later stage when the incipient fire has grown in size and falls more into the detector optical field of view. But such a delay in response is typically undesired because the consequence of a larger fire is usually much greater. It is usually highly desired, that any fire breakout be detected as early as possible so that fire mitigation action can be triggered at an earlier stage, so that the fire is extinguished before it has the time to grow larger in size.